As a known target unit for generation of X-rays provided in an X-ray generation device, there is a target unit including a substrate and a target buried in the substrate (e.g., cf. Patent Literature 1: Japanese Unexamined Patent Publication No. 2004-028845). In the target unit for generation of X-rays described in Patent Literature 1, a single columnar metal wire comprised of tungsten or molybdenum is buried in the substrate comprised of a light element such as beryllium or carbon.